>>41712
Yeah, Ran also has battle scenes, but the drama around the shogun's family is the central theme. I suspect that's Kurosava's style.
Why specifically this period? Anything from any other period (even if it's hypothetical, like Ran) will look like fairly the same. Well, Sengoku had rifles, but for example the struggle between the Fujiwaras, Tairas, and Minamotos (can't remember the name of the period from the top of my head), was very similar in appearance.